Heat energy-powered electrochemical cells

ABSTRACT

The present disclosure provides a heat energy-powered electrochemical cell including an anode, a cathode, and a solid metal polymer/glass electrolyte. The solid metal polymer/glass electrolyte includes between 1% and 50% metal polymer by weight as compared to total solid metal polymer/glass electrolyte weight and between 50% and 90% solid glass electrolyte by weight as compared to the total solid metal polymer/glass electrolyte weight. The solid glass electrolyte includes a working cation and an electric dipole. The heat energy-powered electrochemical cells may be used to capture heat from a variety of sources, including solar hear, waste heat, and body heat. The heat energy-powered electrochemical cells may be fabricated at large-area, thin cells.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/691,344 filed Nov. 21, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/782,443 filed Oct. 12, 2017, now U.S. Pat. No.10,490,360 issued Nov. 26, 2019.

TECHNICAL FIELD

The present disclosure relates to electrochemical cells containing asolid metal polymer/glass electrolyte that are powered by heat energy.

BACKGROUND

An electrochemical cell has two electrodes, the anode and the cathode,separated by an electrolyte. In a traditional electrochemical cell,materials in these electrodes are both electronically and chemicallyactive. The anode is a chemical reductant and the cathode is a chemicaloxidant. Both the anode and the cathode are able to gain and lose ions,typically the same ion, which is referred to as the working cation ofthe battery. The electrolyte is a conductor of the working cation, butnormally it is not able to gain and lose ions. The electrolyte is anelectronic insulator, it does not allow the movement of electrons withinthe battery. In a traditional electrochemical cell, both or at least oneof the anode and the cathode contain the working cation prior to cyclingof the electrochemical cell.

The electrochemical cell operates via a reaction between the twoelectrodes that has an electronic and an ionic component. Theelectrolyte conducts the working cation inside the cell and forceselectrons also involved in the reaction to pass through an externalcircuit.

A battery may be a simple electrochemical cell, or it may be acombination of multiple electrochemical cells.

Rechargeable electrochemical cells and rechargeable batteries containingsuch electrochemical cells are typically charged using electrical energyfrom an external power source.

SUMMARY

The present disclosure provides a heat energy-powered electrochemicalcell including an anode, a cathode, and a solid metal polymer/glasselectrolyte. The solid metal polymer/glass electrolyte includes between1% and 50% metal polymer by weight as compared to total solid metalpolymer/glass electrolyte weight and between 50% and 90% solid glasselectrolyte by weight as compared to the total solid metal polymer/glasselectrolyte weight. The solid glass electrolyte includes a workingcation and an electric dipole.

The following additional features may be combined with the heatenergy-powered electrochemical cell above, with any other features inthe specification, and with one another in any combinations unlessclearly mutually exclusive:

i) the heat energy-powered electrochemical cell may delivers, at a giventemperature or within a given temperature range, at least 85% as muchelectric power (P_(dis)) as an electrochemical cell having the sameanode, the same cathode, and the solid glass electrolyte but lacking themetal polymer;

ii) the heat energy-powered electrochemical cell may deliver, at a giventemperature or within a given temperature range, at least 125% as muchelectric power (P_(dis)) as an electrochemical cell having the sameanode, the same cathode, and the solid glass electrolyte but lacking themetal polymer;

iii) the heat energy-powered electrochemical cell may have a Young'smodulus of less than 120 GPa/mm²;

iv) the solid metal polymer/glass electrolyte may have a Young's modulusof less than 120 GPa/mm²;

v) the heat energy-powered electrochemical cell may have a surface areaof a largest external surface of at least 1 m²;

vi) the solid metal polymer/glass electrolyte may have an ionicconductivity that is at least 25% of the ionic conductivity of the solidglass electrolyte at 25° C.;

vii) the anode may include a metal foil;

viii) the anode may include carbon;

ix) the metal polymer may include a metal polyacrylate;

x) the metal polyacrylate may include sodium polyacrylate;

xi) the metal polymer may include a metal polyethylene glycol;

xii) the metal in the metal polymer may include sodium (Na), lithium(Li), or aluminum (Al);

xiii) the solid metal polymer/glass electrolyte may adhere to thecathode, the anode, or both;

xiv) the working cation may include lithium ion (Li⁺), sodium ion (Na⁺),potassium ion (K⁺) magnesium ion (Mg²⁺), copper ion (Cu⁺) or aluminumion (Al³⁺);

xv) the dipole may have the general formula A_(y)X_(z) or the generalformula A_(y-1)X_(z) ^(−q), wherein A is Li, Na, K, Mg, and/or Al, X isS and/or O, 0<z≤3, y is sufficient to ensure charge neutrality ofdipoles of the general formula A_(y)X_(z), or a charge of −q of dipolesof the general formula A_(y-1)X_(z) ^(−q), and 1≤q≤3;

xvi) the dipole may include up to 50 wt % of the solid glass electrolyteweight of a dipole additive;

xvii) the dipole additive may include one or a combination of compoundshaving the general formula A_(y)X_(z) or the general formulaA_(y-1)X_(z) ^(−q), wherein A is Li, Na, K, Mg, and/or Al, X is S, O,Si, and/or OH, 0<z≤3, y is sufficient to ensure charge neutrality ofdipole additives of the general formula A_(y)X_(z), or a charge of −q ofdipole additives of the general formula A_(y-1)X_(z) ^(−q), and 1≤q≤3;

xviii) the cathode may include a metal foil;

xix) the cathode may include carbon;

xx) the cathode may include a metal foam;

xxi) the cathode may include a metal oxide.

xxii) the heat energy-powered electrochemical cell may be powered bysolar heat;

xxiii) the heat energy-powered electrochemical cell may be powered bybody heat;

xxiv) the heat energy-powered electrochemical cell may be powered bywaste heat;

The present disclosure further includes a heat energy-powered batterysystem including any heat energy-powered electrochemical cell above orotherwise herein.

The present disclosure also includes a heat energy-powered batterysystem including any heat energy-powered electrochemical cell above orotherwise herein and a rechargeable battery or fuel cell electricallyconnected to the heat energy-powered electrochemical cell.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic, cross-sectional diagram of a heat energy-poweredelectrochemical cell according to the present disclosure.

FIG. 2 is a photograph of a heat energy-powered Al/Na+-glass+polymer/Cuelectrochemical cell powering an LED.

DETAILED DESCRIPTION

The present disclosure relates to heat energy-powered electrochemicalcells and heat energy-powered batteries, as well as various devicescontaining such heat energy-powered electrochemical cells and heatenergy-powered batteries and ways to use such electrochemical cells andbatteries. These heat energy-powered devices may convert heat energyinto direct-current electric power.

A heat energy-powered electrochemical cell 10 such as depicted in FIG.1, contains two electrodes 20, a cathode 20 a and an anode 20 b, with asolid metal polymer/glass electrolyte 30 as described herein betweenthem. Electrodes 20 may be large-area electrodes. Solid metalpolymer/glass electrolyte 30 includes a solid glass electrolyte 40,depicted as the dipoles it contains, and a metal polymer 50. The heatenergy-powered electrochemical cell uses a working cation, which may bean alkali-metal cation, such as Li³⁰, Na⁺, K⁺, or a metal cation, suchas Mg²⁺, Cu³⁰, and/or Al³⁺. The heat energy-powered electrochemical cellmay be an all solid-state electrochemical cell.

A battery, such as a heat energy-powered battery of the presentdisclosure, contains an electrochemical cell with at least additionalcomponent, such as another electrochemical cell, a casing, electricalcontacts, control equipment, such as a computer or processor, or a meteror sensor, or safety equipment, such as a cut-off switch or firesuppression equipment. A battery may, therefore, be as simple as a coincell, jelly roll, or prismatic cell, or as complex as an automobile orother vehicle battery or a large grid, home, or industrial storagebattery. A heat energy-powered battery of the present disclosure may bean all solid-state battery.

Heat energy-powered electrochemical cells are described moreparticularly below, but the disclosure is equally applicable to heatenergy-powered batteries containing such heat energy-poweredelectrochemical cells.

Heat-Energy Powering and Self-Charge/Self-Cyclizing

Heat energy-powered electrochemical cells of the present disclosureexhibit self-charge and self-cycling behaviors as well. Self-charge is acharging reaction in an electrochemical cell in the absence of anapplied charging electric power (P_(ch)) at open circuit. The chemicalreaction of an electrochemical cell includes an ionic component,typically involving the working cation, and an electronic component,involving electron transfer. Self-charging occurs where the ioniccomponent of the chemical reaction of the electrochemical cell isbetween the anode and the electrolyte rather than between the twoelectrodes, as in traditional electrochemical cells, but the electroniccomponent remains between the two electrodes, as in traditionalelectrochemical cells. The self-charge and an associated self-cyclingphenomenon occur where the electrolyte contains not only a workingcation with a high ionic conductivity, but also electric dipoles with aslower translational mobility.

At open circuit, no electronic current flows, and the open-circuitvoltage V_(oc) of a electrochemical cell is the difference in thechemical energies (Fermi levels) of the two electrodes (which may simplybe current collectors) divided by the magnitude, e, of the electroncharge. The driving force for a chemical reaction in an electrochemicalcell at open circuit is the requirement that the chemical energies oftwo materials in contact with one another at a heterojunction interfacebe equalized; the chemical reaction creates an electric double-layercapacitor (EDLC) across heterojunction interfaces by the motion and/orcreation of charged particles across or on either side of the interface.The EDLC at the electrode/electrolyte interface in a traditionalelectrochemical cell is created at open-circuit by the motion ofpositively charged working cations in the electrolyte toward the anodeand away from the cathode, with the creation of mirror electroniccharges in the electrodes, which are typically metallic.

In self-charging and self-cycling electrochemical cells, there are twodifferent types of positive charges in the electrolyte, fast-movingworking cations and much slower-moving electric dipoles. As a result,the fast-moving cations can create the needed EDLC to equilibrate theFermi energies of the materials either side of an electrode/electrolyteinterface junction. However, on the later arrival of the slower-movingelectric dipoles that move in the electric field created across theelectrolyte by the cation redistribution, an overcharge across the EDLCcan be adjusted by plating the working cations across the interface ontothe anode to give a self-charge current. At closed-circuit, aself-charge current may add to or subtract from a discharge or chargingcurrent.

Self cycling occurs where the working cation of the electrolyte isplated on an electrode, which charges the electrolyte negative. Thenegative charge in the electrolyte, when large enough, strips the platedmetal back to the electrolyte as cations and releases electrons to theexternal circuit. The different rates of response of the dipoles andions in the electrolyte and the electrons to the external circuit resultin a cycling of the currents in the external circuit and/or the cellvoltage.

Although both self-charging and self-cycling behaviors may occur withoutan external energy input, both phenomena may also occur as a componentof the cell charge/discharge performance with an externalcharge/discharge input. For example, a self-charging electrochemicalcell may be provided with a charging current as an external energyinput, in which case it will exhibit a greater charge than is dictatedby the charging current to give a coulomb efficiency greater than 100%.As another example, the discharge current and/or voltage may have aself-cycling component of frequency that is different from thecharge/discharge cycling frequency.

On discharge, an electrochemical cell or a battery delivers electricpower (P_(dis)) that is the product of the discharge current (I_(dis))and the discharge voltage (V_(dis)) (P_(dis)=I_(dis)V_(dis)). In abattery containing multiple electrochemical cells, the cells may beconnected in series to obtain a particular battery discharge voltage(V_(dis)) and in parallel to provide a particular battery dischargecurrent (I_(dis)).

The discharge current (I_(dis)) of an electrochemical cell depends onthe mobility of the working cation and how readily it may be plated fromthe electrolyte to the electrode or stripped from the electrode into theelectrolyte. Both of these properties are influenced by temperature.Accordingly, the discharge current (I_(dis)) and ultimately the electricpower (P_(dis)) delivered by any electrochemical cell depends somewhaton temperature. However, in a heat energy-powered electrochemical cellof the present disclosure, the dipoles in the polymer/glass electrolytehave a high dielectric constant, leading to a much greater influence oftemperature on electric power (P_(dis)) than in traditionalelectrochemical cells.

A heat energy-powered electrochemical cell or a heat energy-poweredbattery of the present disclosure may deliver, at a given temperature orwithin a given temperature range, at least 85%, at least 90%, at least95%, at least 100%, at least 125%, or at least 150% as much electricpower (P_(dis)) as a comparable electrochemical cell containing only thesolid glass electrolyte component of the solid/polymer glass electrolytedisclosed herein.

Flexibility

A heat energy-powered electrochemical cell of the present disclosure mayalso be flexible. For example, it may have a Young's modulus of lessthan 120 GPa/mm², less than 70 GPa/mm², less than 50 GPa/mm², less than20 GPa/mm², less than 10 GPa/mm², or less than 5 GPa/mm².

A heat energy-powered electrochemical cell of the present disclosure maycontain a solid metal polymer/glass electrolyte with a Young's modulusof less than any of the above limits. Such a solid metal polymer/glasselectrolyte may, therefore, have a Young's modulus at least 10% lower,at least 25% lower, at least 50% lower, at least 75% lower, or at least90% lower than the Young's modulus of an otherwise chemically identicalsolid glass electrolyte lacking a metal polymer.

A heat energy-powered electrochemical cell of the present disclosure maybe able to have a large surface area, measured in the external surfacearea of either electrode. For example, the surface area may be at least0.05 m², 0.1 m², 0.5 m², 1 m², at least 3 m², or at least 6 m².

The solid metal polymer/glass electrolyte may also be formed into sheetshaving a surface area of at least 0.05 m², 0.1 m², 0.5 m², 1 m², atleast 3 m², or at least 6 m², which may allow its use in large rolls ofelectrochemical cells, and as a separator membrane in flow-throughelectrochemical cells. The solid metal polymer/glass electrolyte may behave a thickness of less than 5 mm, less than 1 mm, or less than 0.5 mm,even when formed with the surface areas described above.

Water Insensitivity

The metal polymer in the heat energy-powered electrochemical cells ofthe present disclosure may make them less sensitive to water thanelectrochemical cells lacking the metal polymer. This may beparticularly true when the metal polymer includes a metal acrylate, suchas sodium acrylate. This property may allow heat energy-poweredelectrochemical cells of the present disclosure to be exposed to air forshort durations of time. For example, a roll of heat energy-poweredelectrochemical cell material may be removed from a sealed container,cut into pieces of suitable sizes while exposed to ambient air, thenplaced into a battery. This may particularly facilitate installation ofthe heat energy-powered electrochemical cell material in largerstructures, such as buildings and industrial installations. It may alsodecrease manufacturing costs for heat energy-powered batteries ascompared to batteries containing more water-sensitive materials. Inaddition, the ease with which heat energy-powered electrochemical cellsof the present disclosure can be handles facilitates adaptive batteryconfigurations as well. For example, if more voltage is needed andcapacity can be reduced, a sheet of the heat energy-poweredelectrochemical cell may simply be cut in half and assembled as twoseparate cells in series, doubling the voltage and halving the capacityof the resulting battery.

Solid Polymer/Glass Electrolyte

The solid metal polymer/glass electrolyte is referred to as glassbecause it is amorphous, as may be confirmed through X-ray diffraction.In particular, the solid metal polymer/glass electrolyte may containless than 2% crystalline material, that is not detectable by X-raydiffraction, or no detectable crystalline material, as detected usingX-ray diffraction.

The solid metal polymer/glass electrolyte may be non-flammable and iscapable of plating dendrite-free alkali metals on an electrode currentcollector and/or on itself; the atoms of the plated metal come from theworking cation of the electrolyte; the plated working cations may or maynot be resupplied to the electrolyte from the other electrode.

Where the solid metal polymer/glass electrolyte is neither reduced bythe anode nor oxidized by a high-voltage cathode, including ahigh-voltage storage of electrostatic energy, there is nosolid-electrolyte interphase (SEI) formed at an electrode/electrolyteinterface, and the electrochemical cell can have a long cycle life, suchas over 10,000 cycles.

In particular, the solid metal polymer/glass electrolyte may be anA⁺-glass electrolyte containing as the working cation an alkali-metalcation, such as Li⁺, Na⁺, K⁺ or a metal cation, such as Mg²⁺, Cu⁺, orAl³⁺ as well as electric dipoles such as A₂X or AX⁻, or MgX or Al₂X₃where A=Li, Na, or K and X=O or S or another element or dipole molecule.Suitable A⁺-glass electrolytes and methods of making them have beenpreviously described in WO2015/128834 (A Solid Electrolyte Glass forLithium or Sodium Ion Conduction) and in WO2016/205064 (Water-SolvatedGlass/Amorphous Solid Ionic Conductors), where the alkali-metal-iondisclosures of both are incorporated by references therein.

In general, the metal working cation in the solid metal polymer/glasselectrolyte used in the heat energy-powered electrochemical cells ofthis disclosure may be an alkali-metal ion, such as Li⁺, Na⁺, K⁺, orMg²⁺ or Al³⁺; some of these mobile working cations may also be attachedto an anion to form a less mobile electric dipole such as A₂X, AX⁻, orcondensates of these into larger ferroelectric molecules in which A=Li,Na, K, Mg, Al and x=O, S, or another anion atom. The solid metalpolymer/glass electrolyte may also contain as additives up to 50 w % ofother electric-dipole molecules than those formed form the precursorsused in the glass synthesis without dipole additives. The presence ofthe electric dipoles gives the glass a high dielectric constant; thedipoles are also active in promoting the self-charge and self-cyclingphenomenon. In addition, the solid metal polymer/glass electrolyte arenot reduced on contact with metallic lithium, sodium, or potassium andthey are not oxidized on contact with high-voltage cathodes such as thespinel Li[Ni_(0.5)Mn_(1.5)]O₄ or the olivines LiCo(PO₄) and LiNi(PO₄).Therefore, there is no formation of a passivating solid-electrolyteinterphase (SEI). Also, the surfaces of the solid-glass electrolytes arewet by an alkali metal, which allows plating from the glass electrolytedendrite-free alkali metals that provide a low resistance to transfer ofions across an electrode/electrolyte interface over at least a thousand,at least two thousand, or at least five thousand charge/dischargecycles.

The solid metal polymer/glass electrolyte may be applied as a slurryover a large surface area; the slurry may also be incorporated intopaper, such as carbon paper, or other flexible cellulose or polymermembranes or onto carbon felt or a metal-foam electrode; on drying, theslurry forms a continuous solid metal polymer/glass electrolyte. Themembrane framework may have attached electric dipoles or, on contactwith the glass, forms electric dipoles that have only rotationalmobility. The electric dipoles within the glass may have translationalas well as rotational mobility at 25° C. Reactions between the dipoleswith translational mobility may form dipole-rich regions within theglass electrolyte with some dipole condensation into ferroelectricmolecules; the coalescence of the dipoles, which is referred to as agingof the electrolyte, may take days at 25° C., but can be accomplished inminutes at 100° C.

One or more of the dipoles may have some mobility even at 25° C.

The solid metal polymer/glass electrolyte may have a large dielectricconstant, such as a relative permittivity (σ_(R)) of 10² or higher.Solid metal polymer/glass electrolytes are non-flammable and may have anionic conductivity σ_(A) for the working cation A⁺, of at least 10⁻²S/cm at 25° C. This conductivity is comparable to the ionic conductivityof the flammable conventional organic-liquid electrolytes used in Li-ionbatteries, which makes the cells safe.

The solid metal polymer/glass electrolyte contains both fast-moving ionsand slower moving and/or slower-rotating electric dipoles whereas aconventional electrolyte contains only fast-moving ions. The differenttiming of the fast-moving and slow-moving charges to ananode/electrolyte interface to form an electric-double-layer capacitor(EDLC) and the requirement that the EDLC at the interface retain equalFermi levels (electrochemical potentials) at the interface results in aplating of some fast-moving solid metal polymer/glass electrolytecations on the anode. This process, which does not require replenishmentof the mobile cations from the cathode, represents a self-charge as aresult of an anode-electrolyte chemical reaction; the electroniccomponent of the reaction is, nevertheless, between the two electrodes.

The fast moving ions in the solid metal polymer/glass electrolyte aretypically the working cations. The phenomenon of self-charge occurswhere a solid metal polymer/glass electrolyte contains both fast-movingcations and slower-moving charges of electric dipoles. Atclosed-circuit, the self-charging results in an output powerP_(dis)=I_(dis)V_(dis) that can last for months before an externalcharge P_(ch) is required. The process of self-charge and delivery of aP_(dis) is driven by heat energy, and P_(dis) may increase dramaticallywith the temperature of a cell as it traverses the glass-transitiontemperature.

The solid metal polymer/glass electrolyte may be formed by transforminga crystalline electronic insulator containing the working cation or itsconstituent precursors (typically containing the working cation bondedto O, OH, and/or a halide) into a working-ion-conducting glass/amorphoussolid. This process can take place in the presence of dipole additivesas well. The working cation-containing crystalline, electronic insulatoror its constituent precursors may be a material with the general formulaA_(3-x)H_(x)OX, wherein 0≤x≤1, A is at least one alkali metal, and X isthe at least one halide. Water may exit the solid metal polymer/glasselectrolyte during its formation, particularly due to heating. Water maybe evaporated from the solid metal polymer/glass electrolyte at a highertemperature, such as 230° C. or higher, or between 230° C. and 260° C.

The metal polymer in the solid metal polymer/glass electrolyte mayinclude any metal polymer that can form a composite material with thesolid glass electrolyte without reacting with the solid glasselectrolyte and without reducing the ionic conductivity, such that thesolid metal polymer/glass electrolyte has an ionic conductivity that isat least 25%, at least 50%, at least 75%, or at least 90% of the ionicconductivity of the solid glass electrolyte without metal polymer at 25°C.; or without reducing the ionic conductivity of the solid metalpolymer/glass electrolyte to less than 10⁻² S/cm at 25° C. Some polymersmay actually improve ionic conductivity, for example by increasing ionicconductivity of the solid metal polymer/glass electrolyte by at least5%, at least 10%, at least 25%, or at least 50% as compared to the solidglass electrolyte with the metal polymer at 25° C.

The metal polymer may bond to the solid glass electrolyte withoutreducing or oxidizing the solid glass electrolyte and without hinderingthe mobility of the mobile charges within the glass. The metal polymermay not only render the solid metal polymer/glass electrolytemechanically robust and flexible and enhance bonding with the electrodesor electrode current collectors, but it may also make the also renderthe solid metal polymer/glass electrolyte stable during high-voltagecharge and on contact with alkali-metal anodes undergoing a chargingvoltage.

The metal polymer may contain one or more types of metal, such as sodium(Na), lithium (Li), or aluminum (Al). The polymer may be a copolymer.The metal polymer may be produced by gel polymerization, or by othermethods such as solution or suspension polymerization. The polymer maybe an organic polymer, in particular a polyacrylate, such as sodiumpolyacrylate, or a polyethylene glycol.

The metal polymer may be present in an amount of 1% to 50% by polymerweight/solid metal polymer/glass electrolyte weight.

The metal polymer present in the solid metal polymer/glass electrolyteof the present disclosure may also adhere the solid metal polymer/glasselectrolyte to one or both electrodes in the heat energy-poweredelectrochemical cell. This may make the cell less likely to fail orexperience a performance decrease when subjected to mechanical stressthat tends to separate the electrolyte and electrode(s). In addition,one or both electrodes or other battery in general may lack binders,such as polyvinylidene fluoride (PVDF) and N-methyl-2-pyrolidine (NMP),often used to adhere the electrode(s) to the electrolyte.

In addition, in a solid metal polymer/glass electrolyte in the heatenergy-powered electrochemical cell of the present disclosure may allowthe working cation to plate dendrite-free on the anode.

Electrodes

An electrode used in a heat energy-powered electrochemical cell of thepresent disclosure may include a current collector and/or an activeredox material. An electrode current collector may include a metal, suchas aluminum (Al) or copper (Cu); it may also include a form of carbon,an alloy, or a compound such as titanium nitride (TiN) or atransition-metal oxide. The current collector may be an electrodewithout an active material on it or it may transport electrons to/froman active material on it; the active material may be an alkali metal, analloy of the alkali metal, or a compound containing an atom of theworking cation of the electrolyte. The current collector transportselectrons to or from the external circuit and to or from my activematerial of an electrode reacts with the working cation of theelectrolyte by having electronic contact with the current collector andionic contact with the electrolyte. The ionic contact with theelectrolyte may involve only excess or deficient working-ionconcentration at the electrode/electrolyte interface, which creates anelectric-double-layer capacitor (EDLC), or it may also involve formationof a chemical phase at the electrode surface. In a heat energy-poweredelectrochemical cell of the present disclosure, any chemical formationon an electrode surface as well as the EDLC across theelectrode/electrolyte interface is reversible.

According to the present invention, one or both electrodes in theelectrochemical cell may be, on fabrication, only current collectorscontaining no detectable atom of the working cation of the electrolytedown to 7000 ppm by, for example, atomic absorption spectroscopy.However, after cell assembly, atoms of the working cation of theelectrolyte may be detected on the electrode by atomic absorptionspectroscopy or by other means.

In addition, one or both electrodes of the cell may contain anadditional electronically conductive material such as carbon that aidsplating of the working cation on the current collector without changingsignificantly the effective Fermi level of the composite currentcollector.

The cathode may also contain a high-voltage active material, such as thespinel Li[Ni_(0.5)Mn_(1.5)]O₄ or an olivine, such as LiFe(PO₄),LiCo(PO₄) and LiNi(PO₄), or another metal oxide. When brittle materialsare used in the cathode or anode, the cathode or anode may contain thesebrittle materials as particles located in other agents, such as polymersor metal foams, that make the more flexible than sheets or largerstructures of the brittle materials could tolerate. This allows the useof brittle electrode active materials in flexible heat energy-poweredelectrochemical cells.

In particular, heat energy-powered electrochemical cells of the presentdisclosure may contain an aluminum (Al) anode and a copper (Cu) cathode.These metals may be present as metal only, or coated with a carbon film.In some examples, particularly for sodium-ion batteries, a more complexcathode, such as a metal oxide (particularly MnO₂)/carbon/metal foamcathode may be used. Cu foam or other metal foam electrodes as well aselectrodes containing carbon felt or carbon cloth may also be used.

The cathode may also be contacted by a particle such as S₈, MnO₂, FePO₄,or a molecule such as ferrocene.

Other electronic conductors that may be used as electrodes or inelectrodes include nickel (Ni), zinc (Zn), lead (Pb), tin (Sn), iron(Fe), or a conductive compound such as TiN or Fe₃O₄.

In some examples, the cathode may be a flow-through cathode, which maybe combined with an alkali-metal anode.

Applications and Uses

Heat energy-powered batteries of the present disclosure may be used in avariety of applications for which traditional batteries or evenbatteries containing the solid glass electrolyte with no polymer are notsuited.

For example, as mentioned above, heat energy-powered batteries may beused in buildings or industrial installations, where they may usesolar-generated or waste heat to create electric power.

Heat energy-powered batteries may use solar-generated heat, but unlike,photovoltaic cells, need to be directly exposed to sunlight because,unlike light, the infrared electromagnetic radiation from the sun, whichprovides heat energy, can travel through opaque materials. Heatenergy-powered batteries may be able to transform to electric power theheat generated by the entire spectrum of solar radiation during the dayand waste heat during both night and day. This ability provides moreinstallation options as well as lower-cost fabrication and maintenance.In addition, some problems associated with photovoltaic cells may beavoided, such as decreases in performance due to the accumulation ofdust and other opaque materials. Furthermore, heat-energy poweredbatteries may be installed near any heat source, not just on a rooftop

In addition, the flexibility of heat energy-powered electrochemicalcells and heat energy-powered batteries of the present disclosure mayfacilitate use in buildings or industrial applications, where customsizing and curved or sharp features may need to be accommodated.

In some examples, heat energy-powered batteries may be installed in theroof of a building. This allows the heat energy-powered batteries toturn both solar heat energy and waste heat energy escaping the roof ofthe building to be used to create electric power. The heatenergy-powered batteries may be installed as an outer roof layer, orunder a protective material, such as shingles or another roofingmaterial. The heat energy-powered batteries may even be installed on theinterior roof surface of the building, or under an interior layer, suchas a ceiling material. When heat energy-powered batteries are installedon an outer roof layer, the outer roof layer may be adapted tofacilitate electric power creation. For instance, the outer roof layermay have an infrared reflectivity designed to maintain the heatenergy-powered batteries in a particular temperature range during aportion of daylight hours.

Heat energy-powered batteries may also be installed on or in interior orexterior walls of buildings. For instance, in particularly cold climateswhere heat energy in the form of waste heat being lost from thestructure may be a substantial heat energy source, heat energy-poweredbatteries may be included in the walls of the structure, or at least theupper portions of walls.

Heat energy-powered batteries may further be included in interior wallssurrounding heat-generating equipment, such as water heaters, laundryequipment, fossil fuel-powered automobiles, fossil fuel-poweredindustrial generators or motors, and other heated or heat-generatingindustrial equipment.

Heat energy-powered batteries may also be installed around pipes andtanks in homes.

Particularly in industrial settings, heated or heat-generatingequipment, particularly pipes and tanks, may be covered with heatenergy-powered batteries of the present disclosure.

Heat energy-powered batteries may also be used in wearable electronicdevices, such as watches and clothing, where they may create electricpower from body heat.

Heat energy-powered batteries may also be used in hand held devices,where heat from the user's hand may be used to create electric power.

Heat energy-powered batteries may be used around or near any combustiondevice to capture waste heat.

Heat energy-powered batteries may further be used in vehicles,particularly to capture heat from heat-generating components, such asfossil fuel-powered motors, including fossil fuel-powered generators inhybrid electric vehicles. Heat energy-powered batteries may also belocated in parts of vehicles that are commonly exposed to sunlight, suchas the roofs and hoods of cars, buses, and trucks, the wings and upperfuselage of airplanes and drones, and the decking and uppersuperstructure of boats, including cargo covers, sails, and solar energycollection structures. Heat energy-powered batteries may also collectwaste heat from other energy sources, such as engines, in these andother types of vehicles.

Heat energy-powered batteries may also be used to improve the energyefficiency or practical availability of equipment already adapted foruse with rechargeable batteries or photovoltaic cells. For example,power tool batteries may include a heat energy-powered batteries,allowing spare batteries to be recharged simply by placing them in asunny location at a worksite. Batteries for portable medical equipment,such as is often used by the military, in less-developed locates, orduring epidemic responses may be charged in the same manner. Inaddition, heat energy-powered batteries may enable or extend nighttimeuse of some portable medical equipment that currently relies onphotovoltaic cells by instead allowing the use of body heat or anotherheat source to create electric power.

Heat energy-powered batteries may also be used in place of photovoltaiccells in grid energy production, such as on solar energy farms. Hybridenergy generation devices, such as devices with photovoltaic cells ontop with heat energy-powered batteries underneath to absorb heat energythat passes through the photovoltaic cells are also possible.

Heat from the body and/or the sun may be used to rechargebattery-powered mobile devices carried personally or battery powereddevices used in remote locations. These devices may include medicalequipment, communication devices, or mechanical equipment. Less costlyheat energy-powered batteries that transform heat energy into electricpower may replace photoelectric devices for the storage ofsolar-generated electric power in a rechargeable battery or for theproduction of a chemical commodity such as hydrogen from theelectrolysis of water.

In addition, heat energy-powered batteries of the present disclosure arereadily combinable with other energy storage components, such astraditional rechargeable batteries or fuel cells, allowing the electricpower created using heat energy to be stored for later use, for instancewhen the ambient temperature has decreased.

EXAMPLES

The following examples are provided to further illustrate the principlesand specific aspects of the invention. They are not intended to andshould not be interpreted to encompass the entire breath of all aspectsof the invention.

Example 1

A heat energy-powered electrochemical cell may be prepared with analuminum (Al) anode, which may be a metal foil current collector. Thefoil may also be coated with carbon.

The heat energy-powered electrochemical cell may also have a solid metalpolymer/glass electrolyte, which may include sodium polyacrylate as themetal polymer and an A⁺-glass, where A is lithium (Li), sodium (Na), orpotassium (K) as the glass. Specifically, the A⁺-glass may be formedfrom a ceramic A_(3-x)H_(x)OX, X=Cl or Br precursor by addition of asmall percentage (≤1 w %) of a hydrated hydroxide such as Ba(OH)₂x H₂O,x≤10, to form a dry, amorphous-ceramic dielectric electrolyte. The solidmetal polymer/glass electrolyte may be formed with an A⁺-polyacrylate aspolymer.

The heat energy-powered electrochemical cell may be prepared with acopper (Cu) cathode, which may be a metal foil collector. The foil maybe coated with carbon film.

Such a heat energy-powered electrochemical cell may exhibit self-charge,a long self-charge/discharge cycle life, mechanical robustness andtolerance of heat fluctuations, changing ambient-air environments,water, and mechanical abuse. Such a heat energy-powered electrochemicalcell may also be easy to fabricate, even as a large surface area sheet,such as in a large-area thin cell.

Such a heat energy-powered electrochemical cell is illustrated in FIG. 2lighting a red light-emitting diode (LED) even though the cell membraneis bent by nearly 90°. This example illustrates the mechanically robustnature of the solid metal polymer/glass electrolyte in a heatenergy-powered electrochemical cell as well as the ability to deliverelectric-power without the application of an external P_(ch). However,the cell was first charged and fully discharged before the demonstrationwas made. It should be noted that neither electrode initially containedthe mobile A⁺ cation of the electrolyte. The notation for a cell is asfollows: cathode/electrolyte/anode.

Example 2

A heat energy-powered electrochemical cell was prepared with a metallicsodium (Na) anode, a solid metal polymer/glass electrolyte, whichincluded 10 wt % sodium polyacrylate as the metal polymer and aNa⁺-glass as the glass, and Cu foam cathode containing manganese oxide(MnO₂) and carbon (C). The anode and cathode originally lacked Na⁺working cation.

MnO₂ particles in the cathode determine the dominant potential of thecathode and were not reduced by discharge of the heat energy-poweredelectrochemical cell. The cell exhibited a self-charge with aV_(dis)≃3.0 V.

Example 3

A heat energy-powered electrochemical cell was prepared with an Alanode, a carbon and Cu cathode that originally lacked the Na⁺ workingcation, a solid metal polymer/glass electrolyte, which included 10 wt %sodium polyacrylate as the metal polymer and a Na⁺-glass as the glass.The cell was cut into two or more pieces that were connected in seriesto form multicell batteries that powered red, white, and blue LEDs usingelectric power derived from heat energy.

Example 4

A heat energy-powered electrochemical cell was prepared as in Example 3,but with a carbon felt cathode. This electrochemical cell wasdemonstrated to transform ambient heat into electric power at 25° C.

Example 5

A heat energy-powered electrochemical cell was prepared as in Example 3,but with a carbon on copper foam cathode. This electrochemical cell wasdemonstrated to transform ambient heat into electric power at 25° C.

Example 6

A heat energy-powered electrochemical cell may be prepared with an Alanode, a solid metal polymer/glass electrolyte, which included 10 wt %sodium polyacrylate as the metal polymer and a Na⁺-glass as the glass,and a Cu foil cathode. The anode and cathode originally lacked Na⁺working cation.

The heat energy-powered electrochemical cell was fabricated as alarge-area thin cell. The discharge current (I_(dis)) of this cellincreased a factor of seven after being transported from anair-conditioned laboratory to outdoor solar heat at approximately 30-40°C. delivered through a protective plastic cover.

In addition, the large-area thin cell increased its discharge voltage(V_(dis)) with increasing temperature from 0 V at 25° C. to 0.91 V at72° C.

Example 7

A heat energy-powered electrochemical cell may be prepared with ametallic lithium (Li), a solid metal polymer/glass electrolyte, and aflow-through cathode. The heat energy-powered electrochemical cellfunctioned with the solid metal polymer/glass electrolyte as aseparator.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments which fall within thetrue spirit and scope of the present disclosure. Thus, to the maximumextent allowed by law, the scope of the present disclosure is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents and shall not be restricted or limited bythe foregoing detailed description.

The invention claimed is:
 1. A vehicle comprising: a heat-generatingcomponent, a part commonly exposed to sunlight, or both; and a heatenergy-powered electrochemical cell comprising: an anode; a cathode; anda solid metal polymer/glass electrolyte, wherein the metal polymer andthe glass electrolyte are intermixed with each other comprising: between1% and 50% metal polymer by weight as compared to total solid metalpolymer/glass electrolyte weight; and between 50% and 90% solid glasselectrolyte by weight as compared to the total solid metal polymer/glasselectrolyte weight, wherein the solid glass electrolyte comprises: aworking cation; and an electric dipole.
 2. The vehicle of claim 1,wherein the vehicle comprises a heat-generating component and the heatenergy-powered electrochemical cell is positioned to capture heat fromthe heat-generating component.
 3. The vehicle of claim 1, wherein thevehicle comprises a part commonly exposed to sunlight and the heatenergy-powered electrochemical cell is located in the part commonlyexposed to sunlight.
 4. The vehicle of claim 3, wherein the partcommonly exposed to sunlight comprises a roof or hood of a car, bus, ortruck.
 5. The vehicle of claim 3, wherein the part commonly exposed tosunlight comprises a wings or upper fuselage of an airplane or drone. 6.The vehicle of claim 3, wherein the part commonly exposed to sunlightcomprises the decking or upper superstructure of a boat.
 7. The vehicleof claim 6, wherein the decking or upper superstructure of a boatcomprises cargo covers, sails, and solar energy collection structures.8. The vehicle of claim 1, wherein the vehicle comprises an energysource that generates waste heat and the heat energy-poweredelectrochemical cell is positioned to capture the waste heat.
 9. Thevehicle of claim 8, wherein the energy source that generates waste heatis comprises an engine.
 10. The vehicle of claim 1, wherein the heatenergy-powered electrochemical cell delivers, at a given temperature orwithin a given temperature range, at least 85% as much electric power(P_(dis)) as an electrochemical cell having the same anode, the samecathode, and the solid glass electrolyte but lacking the metal polymer.11. The vehicle of claim 1, wherein the heat energy-poweredelectrochemical cell delivers, at a given temperature or within a giventemperature range, at least 125% as much electric power (P_(dis)) as anelectrochemical cell having the same anode, the same cathode, and thesolid glass electrolyte but lacking the metal polymer.
 12. The vehicleof claim 1, wherein the heat energy-powered electrochemical cell has aYoung's modulus of less than 120 GPa/mm².
 13. The vehicle of claim 1,wherein the solid metal polymer/glass electrolyte has a Young's modulusof less than 120 GPa/mm².
 14. The vehicle of claim 1, wherein the heatenergy-powered electrochemical cell has a surface area of a largestexternal surface of at least 1 m².
 15. The vehicle of claim 1, whereinthe solid metal polymer/glass electrolyte has an ionic conductivity thatis at least 25% of the ionic conductivity of the solid glass electrolyteat 25° C.
 16. The vehicle of claim 1, wherein the anode comprises ametal foil.
 17. The vehicle of claim 1, wherein the anode comprisescarbon.
 18. The vehicle of claim 1, wherein the metal polymer comprisesa metal polyacrylate.
 19. The vehicle of claim 18, wherein the metalpolyacrylate comprises sodium polyacrylate.
 20. The vehicle of claim 1,wherein the metal polymer comprises a metal polyethylene glycol.
 21. Thevehicle of claim 1, wherein the metal in the metal polymer comprisessodium (Na), lithium (Li), or aluminum (Al).
 22. The vehicle of claim 1,wherein the solid metal polymer/glass electrolyte adheres to thecathode, the anode, or both.
 23. The vehicle of claim 1, wherein theworking cation comprises lithium ion (Li⁺), sodium ion (Na⁺), potassiumion (K⁺) magnesium ion (Mg²⁺), copper ion (Cu⁺), or aluminum ion (Al³⁺).24. The vehicle of claim 1, wherein the dipole has the general formulaA_(y)X_(z) or the general formula A_(y-1)X_(z) ^(−q), wherein A is Li,Na, K, Mg, and/or Al, X is S and/or O, 0<z≤3, y is sufficient to ensurecharge neutrality of dipoles of the general formula A_(y)X_(z), or acharge of −q of dipoles of the general formula A_(y-1)X_(z) ^(−q), and1≤q≤3.
 25. The vehicle of claim 24, wherein the dipole comprises up to50 wt % of the solid glass electrolyte weight of a dipole additive. 26.The vehicle of claim 25, wherein the dipole additive comprises one or acombination of compounds having the general formula A_(y)X_(z) or thegeneral formula A_(y-1)X_(z) ^(−q), wherein A is Li, Na, K, Mg, and/orAl, X is S, O, Si, and/or OH, 0<z≤3, y is sufficient to ensure chargeneutrality of dipole additives of the general formula A_(y)X_(z), or acharge of −q of dipole additives of the general formula A_(y-1)X_(z)^(−q), and 1≤q≤3.
 27. The vehicle of claim 1, wherein the cathodecomprises a metal foil.
 28. The vehicle of claim 1, wherein the cathodecomprises carbon.
 29. The vehicle of claim 1, wherein the cathodecomprises a metal foam.
 30. The vehicle of claim 1, wherein the cathodecomprises a metal oxide.
 31. The vehicle of claim 1, further comprisinga rechargeable battery or fuel cell electrically connected to the heatenergy-powered electrochemical cell.